The CEO (Consumer Electronics Control in English) protocol is a protocol allowing two electronic apparatuses to dialogue via an HDMI interface. The CEO protocol makes it possible to create automated strings of commands between several electronic apparatuses connected together. These strings of commands are performed via an HDMI interface available on a “main” electronic apparatus, into which all the electronic apparatuses are directly or indirectly plugged. Thus, the user of these apparatuses will benefit from global control and from a simplification of the system comprising these electronic apparatuses, by reducing the number of useful remote controls.
Thus, the CEO protocol makes it possible to architecture an audio/video system comprising several multimedia apparatuses including apparatuses for multimedia reproduction in a tree-like manner:                the root being constituted by a multimedia reproduction apparatus, for example, the television,        the branches by multimedia apparatuses connected to this reproduction apparatuses such as switchers, amps, recorders, etc., and        the leaves by multimedia apparatuses sourcing multimedia data notably various audio/video sources such as DVD/HD reader, games console, digital terminal, camcorder, etc.        
When the user inserts a disk into a reader connected to a reproduction apparatus, and commands the “Reading” of the disk by the reader, the HDMI interface implementing the CEO protocol commands the other multimedia apparatuses connected to the reader and necessary for the reproduction of the disk for the user, namely:                to command the activation of the television (only if it was on standby) and the toggling of the reproduced port onto the input connected to the reader,        optionally to command the activation of the amplifier and the toggling of the reproduced port onto the input connected to the reader.        
When the user places his television on standby, he often forgets to place on standby the various electronic apparatuses connected to the television such as their decoder or “Set Top Box” (STB). The CEO protocol thus makes it possible, through a simple string of commands, to trigger the placing of the decoder or “Set Top Box” on standby.
The CEO protocol not being implemented in all electronic apparatuses: if the “root” apparatus does not implement the CEO protocol, the latter cannot be used and the user finds himself in a configuration of a system composed of electronic apparatuses that he has to control individually. If the “root” apparatus implements the CEO protocol but the decoder or “Set Top Box” does not implement it, the user can control in a grouped manner the television and the “branch” and “leaf” apparatuses connected to this television implementing the CEO protocol but in an individual manner the decoder or “Set Top Box”.
Furthermore, today the constructors of electronic apparatuses are developing proprietary command string protocols for the control of various electronic apparatuses of one and the same electronic system, in particular in the audiovisual (AV) field. Notably, Panasonic's Viera Link protocol, Sony's Bravia Theater Sync protocol, Samsung's Anynet+ protocol, Toshiba's Regza Link protocol or Sharp's Aquos Lonk protocol are proprietary protocols compatible with the HDMI standard affording these command strings as a supplement. Thus, these protocols not necessarily being mutually compatible, and the decoders or “Set Top Box” being rarely, or indeed depending on country, ever manufactured by the constructor of the televisions, the user must generally control his decoder or “Set Top Box” in an individual manner even when his television implements such a proprietary command string protocol.